Exhaust Kit for GMC Sierra (2016-2018) 4.3L 5.3L 6.2L

High-Flow Dual Muffler-Back Exhaust Kit for 2016-2018 GMC Sierra (K2XX)

What it Does: The dual muffler-back exhaust kit replaces the restrictive factory muffler and single tailpipe on the 2016-2018 GMC Sierra to reduce exhaust gas backpressure, improve scavenging, and optimize acoustic flow.

The Stock GMC Sierra Exhaust Restriction and Acoustic Dampening

Factory exhaust assemblies on the K2XX platform utilize oversized, baffled single-inlet mufflers designed strictly for sound attenuation rather than flow efficiency. These internal chambers restrict exhaust velocity, trap excessive heat forward of the rear axle, and suppress exhaust scavenging on high-displacement platforms. Furthermore, the OEM single exit limits volume and throttle response under heavy engine loads.

The Engineering Solution

This kit upgrades the exhaust architecture utilizing a Flowsound 2-chamber muffler with a 3.00-inch inlet splitting into dual 2.50-inch outlets. Paired with 2.5-inch mandrel-bent aluminized steel tailpipes, the continuous-radius bends eliminate internal crimping to maintain uniform gas velocity and structural integrity. Routed parallel to the frame rails, the geometry retains vital clearance around the factory spare tire and OEM receiver hitch while surviving high duty-cycle thermal expansion.

What's Included

• 1 Flowsound 2-chamber muffler (single 3-inch inlet, dual 2.5-inch outlets)
• 2 Aluminized mandrel-bent two-piece 2.5-inch tailpipes (slip-fit configuration)
• 8 Muffler clamps
• 1 Heavy-duty exhaust clamp
• 4 Rubber-insulated mounting hangers

Technical Specifications

Compatibility

• 2016-2018 GMC Sierra 1500 4.3L V6 EcoTec3 (LV3) Gasoline/Flex-Fuel
• 2016-2018 GMC Sierra 1500 5.3L V8 EcoTec3 (L83) Gasoline/Flex-Fuel
• 2016-2018 GMC Sierra 1500 6.2L V8 EcoTec3 (L86) Gasoline
• Fits all standard wheelbases with factory single-inlet muffler configurations only

Frequently Asked Questions & Fitment Warnings

Does this fit the K2XX Sierra?

Yes, this system fits 2016-2018 GMC Sierra trucks equipped with the LV3, L83, or L86 engines; it is not compatible with dual-inlet factory mufflers, diesel variants, or 2500HD/3500HD chassis.

Is this exhaust system a direct bolt-on installation?

No, this is a custom-fit builder kit requiring an experienced installer to measure, cut, or adapt pipe sections forward of the muffler depending on cab length and wheelbase.

The GMC Sierra Towing Caliber

Engineered to handle severe towing cycles and heavy payloads, this aluminized steel setup provides the durability and heat resistance required for heavy working conditions without compromising critical frame or suspension clearances.